[bravoghost]

So a blackbody will emit light with a higher frequency the hotter the blackbody gets, right? A piece of coal at 1000K emits red light, and at 2000K it is a white light. And I assume this light is on a continuum, so that at 1500K the light was a mix between white and red (orange-ish?).

So why was this phenomenon unexplainable by classical physics? And how did it help prove quantized energy theory? The light from the coal isn't changing according to quantized levels - it is on a continuum - so how does that relate to anything quantized?

[Yggdrasil]

The explanation is complicated but basically, classical theories of light (assuming it is purely oscillations of electrical and magnetic fields) predicted blackbodies would radiate infinite amounts of energy at short wavelenghts (the so called ultraviolet catastrophe).  Planck's theory of blackbody radiation, based on a quantum theory of light, was able to correctly predict the emission spectrum of a blackbody, providing evidence that light is quantized.

[bravoghost]

AH! Thanks!